Fruit Pest News
Volume 10, No. 11 July 10, 2009
An online newsletter whose goal is to provide all interested persons with timely information on diseases and insects of commercial fruit and vegetable crops in Tennessee.
Text appearing in blue or red can be clicked to link to other web sites. Be aware that much of the linked information is produced in other states and may not be applicable to Tennessee.
In This Issue:
1. Recent Diagnostic Notes
2. Cucurbit Downy Mildew -- No Change in Alert Status
3. Revus Fungicide Labeled for Tomatoes and Potatoes
4. Corn Earworm and European Corn Borer
5. Pheromone Trap Catches
1. Recent Diagnostic Notes
Some plant problems that have occurred this year:
Split pit of peach. This is a physiological disorder that can cause the fruit to part (not split, but open) at the stem end and cause gum to form around the pit. The latter can occur without visible symptoms. It is worse on early varieties and in years of light fruit load.
Blossom-end rot of tomato. This physiological disorder has been abundant this year. It is the result of inadequate calcium in the fruit, usually caused by an uneven water supply. Mulching the plants or providing drip irrigation helps to provide a more consistent moisture level. Test the pH level of the soil and add lime if needed. Calcium chloride can be applied to the foliage but is not as helpful as the other steps mentioned.
Acid soil seems to be fashionable this year. Unfortunately, it plays havoc with yield and is not recommended, since yield = money!
Southern blight of vegetables. This plant killer is lurking. If a plant wilts, look at the base. If found, remove from planting if practical. The fungus thrives on plant debris at or near the surface of the soil, as found in reduced-tillage systems. The moldboard plow is not a friend of soil conservation, but is great for controlling southern blight.
Sun-scalded leaves of snap beans. This can occur on snap bean leaves during periods of high light intensity. It is not serious and will not reduce yield. Leaf wilting, caused by anything from southern blight to stink bugs, can increase the amount of sunscald, but is not required for sunscald to occur.
Tomato spotted wilt virus. This has not been a particularly bad year for spotted wilt, but did you know that it can sometimes cause the tomato leaves to be black as tar?
Bacterial
spot of tomato and pepper obtained from garden centers continues to
plague all of TN. No progress is being made in reducing this problem. (SB)
2. Cucurbit Downy Mildew - No Change in Alert Status
Downy mildew remains well to the south and east of Tennessee. See map: http://nc-climate.ncsu.edu/cucurbit/map.php. The sites are some distance from TN, but not so far that air currents couldn't bring us spores without the need for "hop-scotching." They could move here in one weather event. The forecast calls for low risk through the weekend. See "outlook" at this site. Keep an eye on the forecasts ("outlook") at that site, which are issued every Monday, Wednesday, and Friday.
The strategy for protection in TN remains unchanged -- The use of specialized downy mildew fungicides is not recommended until we are under high risk of infection from a spore transport event, or the disease has been found in the field or in the community (That's why we need to let others know when we find or think we find the disease). Until then, use chlorothalonil or mancozeb to protect your crop against this and other fungal diseases. (SB)
3. Revus Fungicide Labeled for Tomatoes and Potatoes
Because of the outbreak of late blight in the Northeast resulting from plants obtained at garden centers, Syngenta has obtained a supplemental label for Revus (mandipropamid) fungicide for potatoes and tomatoes. Revus Top, which contains two active ingredients, is registered for these crops, but the supply was depleted by the demand in the Northeast for this excellent late blight material. Revus is used primarily for Phytophthora capsici control and is also labeled for downy mildew control. (SB)
4. Corn Earworm and European Corn Borer
Peppers and sweet corn need to be
closely monitored especially now that they are producing a crop. Corn earworm moths
tend to lay their eggs on the corn silk. Since the silk can grow about an inch per
day, proper insecticide coverage of the silk requires a short spray interval. This
can mean spraying the silk every two or three days when corn earworm moth activity
is high and egg laying is heavy. It is thus very advantageous for growers to know
when corn earworm and European corn borer moths are active and laying eggs. A useful
spray frequency table from the University of Minnesota based on the number of corn
earworm moths caught per night when sweet corn is silking is available at http://ipm.illinois.edu/fieldcrops/insects/corn_earworm/index.html.
Corn earworm moth activity can be best determined by using a pheromone trap.
The pheromone attracts the male moths of the species. There is an excellent video
available on-line at http://vegnet.osu.edu/ by Dr. Celeste Welty, an Extension Entomologist
at The Ohio University Extension. The video shows step by step how to set up and
use a Scentry Heliothis trap. European corn borers often enter the ear by boring
into the side. European corn borers can be monitored using a blacklight trap (used
primarily by research entomologists) or more commonly a pheromone trap such as Scentry
Heliothis trap or the somewhat larger and heavier metal-mesh Hartstack trap.
Note
that the European corn borer is an important pest of peppers. The caterpillars will
often enter the pepper just under the cap so it is often difficult to even know that
damage has ocurred without periodically cutting open and inspecting some peppers.
Insecticides should be used on a 5-10 day interval when the European corn borer
moths are active. (FH)
5. Pheromone Trap Catches and Biofixes (FH)
Nashville
(Davidson County) Pheromone Trap Catches for 2009
Oriental fruit moth (OFM), redbanded
leafroller (RBLR), obliquebanded leafroller (OBLR), codling moth (CM), grape berry
moth (GBM), variegated leafroller (VLR), black cutworm (BCW), diamondback moth (DBM),
armyworm (AW), beet armyworm (BAW), squash vine borer (SVB), fall armyworm (FAW)
| OFM | RBLR | OBLR | CM | GBM | VLR | BCW | DBM | AW | CL | BAW | SVB | FAW | |
|
3-13 (Put out RBLR trap) |
-- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| 3-20 | -- | 29* | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| 3-23 | -- | 14 | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
|
3-30 (put out BCW trap) |
-- | 9 | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
|
3-31 (put out OFM, CM, VLR, OBLR traps) |
-- | 10 | -- | -- | -- | -- | 0 | -- | -- | -- | -- | -- | -- |
| 4-2 | 4** | 2 | 0 | 0 | -- | 0 | 0 | -- | -- | -- | -- | -- | -- |
|
4-3 (put out AW trap) |
-- | -- | -- | -- | |||||||||
|
4-8 (put out GBM, DBM, BAW, FAW, SVB, CL traps) |
12 | 19 | 0 | 0 | -- | 0 | 2 | -- | 4 | -- | -- | -- | -- |
| 4-13 | 9 | 17 | 0 | 0 | 4*** | 0 | 0 | 0 | 7 | 0 | 0 | 0 | 0 |
| 4-20 | 4 | 7 | 0 | 0 | 5 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
| 4-27 | 6 | 0 | 0 | 0 | 16 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 5-4 | 2 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
| 5-11 | 0 | 0 | 4**** | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 |
| 5-18 | 5 | 0 | 3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 5-21 | 3 | 12 | 23 | 0 | 4 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 5-26 | 7 | 29 | 10 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 6-1 | 7 | 96 | 38 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 |
| 6-10 | 10 | 4 | 18 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 |
| 6-15 | 3 | 2 | 6 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 6-22 | 6 | 2 | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 |
| 6-30 | 5 | 2 | 3 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 |
| 7-7 | 8 | 7 | 16 | 0 | 0 | 0 | 0 | 0 | 0 | 3 | 0 | 0 | 0 |
* Biofix for RBLR in Davidson County estimated as prior to March 20 (trap not
out early enough).
**Biofix for OFM in Davidson County was April 2.
***Biofix
for GBM in Davidson County was April 13.
****Biofix for OBLR in Davidson County
was May 11.
Putnam County Pheromone trap Catches for 2009
Tufted Apple Bud Moth (TABM)
| OFM | RBLR | OBLR | CM | VLR | TABM | |
| 3-16 | -- | 10* | -- | -- | 0 | -- |
| 3-18 | -- | 31 | -- | -- | 0 | -- |
| 3-20 | -- | 2 | -- | -- | 0 | -- |
| 3-23 | -- | 2 | -- | -- | 0 | -- |
| 3-25 | -- | 0 | -- | -- | 0 | -- |
| 3-27 | -- | 6 | -- | -- | 0 | -- |
| 3-30 | -- | 11 | -- | -- | 0 | -- |
|
4-1 (put out OBLR, TABM traps) |
||||||
| 4-3 | -- | 10 | 0 | -- | 0 | 0 |
|
4-10 (put out OFM trap) |
-- | 11 | 0 | -- | 0 | 0 |
| 4-13 | 4 | 3 | 0 | -- | 0 | 0 |
|
4-17 (put out CM trap) |
12 | 9 | 0 | -- | 0 | 0 |
| 4-20 | 10 | 0 | 0 | 2** | 0 | 0 |
| 4-22 | 4 | 0 | 0 | 0 | 0 | 1 |
| 4-24 | 7 | 2 | 0 | 2 | 0 | 2*** |
| 4-27 | 4 | 0 | 0 | 1 | 0 | 0 |
| 5-1 | 5 | 0 | 0 | 0 | 0 | 0 |
| 5-8 | 11 | 0 | 0 | 1 | 0 | 14 |
| 5-15 | 1 | 0 | 0 | 0 | 0 | 15 |
| 5-18 | 3 | 0 | 0 | 1 | 0 | 12 |
| 5-22 | 5 | 14 | 0 | 0 | 0 | 22 |
| 5-25 | 2 | 16 | 3 | 2 | 0 | 1 |
| 5-29 | 0 | 30 | 3 | 1 | 2 | 6 |
*Biofix for RBLR in Putnam County estimated as prior to March 16 (trap not out
early enough).
**Biofix for CM in Putnam County was April 20.
.**Biofix for
TABM in Putnam County was April 24.
Obion County Pheromone Trap Catches for 2009
| VLR | RBLR | OBLR | CM | OFM | |
| 5-1 | 3* | -- | -- | -- | -- |
| 5-12 | 42 | -- | -- | -- | -- |
| 6-1 (Note: missing data [--] prior to June) | 14 | 22 | 2 | 0 | -- |
| 6-18 | 7 | 14 | 1 | 0 | 2 |
| 6-22 | 6 | 14 | 1 | 0 | 2 |
| 6-27 | 4 | 2 | 1 | 0 | 3 |
*Biofix for VLR in Obion County was May 1.
The Fruit Pest News URL is: http://web.utk.edu/~extepp/fpn/fpn.htm
Contacts:
Steve Bost, Professor and Extension Plant Pathologist
Frank Hale, Professor and Extension Entomologist
Both authors available at:
615-832-6802
fax 615-781-2568
Soil, Plant and Pest Center
5201 Marchant Drive
Nashville, TN 37211
Copyright 2009 The University of Tennessee. All rights reserved. This document may be reproduced and distributed for nonprofit educational purposes provided that credit is given to University of Tennessee Extension.
Programs in agriculture and natural resources, 4-H youth development, family and consumer sciences, and resource development. University of Tennessee Institute of Agriculture, U.S. Department of Agriculture and county governments cooperating. UT Extension provides equal opportunities in programs and employment.
